Biology subjects

Fausto, A.

Publications and source records attributed to Fausto, A..

3 recordsLinked to original sources

bioRxiv2023

Interferon signaling in the nasal epithelium distinguishes among lethal and common cold respiratory viruses and is critical for viral clearance

All respiratory viruses establish primary infections in the nasal epithelium, where efficient innate immune induction may prevent dissemination to the lower airway and thus minimize pathogenesis. Human coronaviruses (HCoVs) cause a range of pathologies, but the host and viral determinants of disease during common cold versus lethal HCoV infections are poorly understood. We model the initial site of infection using primary nasal epithelial cells cultured at air-liquid interface (ALI). HCoV-229E, HCoV-NL63 and human rhinovirus-16 are common cold-associated viruses that exhibit unique features in this model: early induction of antiviral interferon (IFN) signaling, IFN-mediated viral clearance, and preferential replication at nasal airway temperature (33{degrees}C) which confers muted host IFN responses. In contrast, lethal SARS-CoV-2 and MERS-CoV encode antagonist proteins that prevent IFN-mediated clearance in nasal cultures. Our study identifies features shared among common cold-associated viruses, highlighting nasal innate immune responses as predictive of infection outcomes and nasally-directed IFNs as potential therapeutics.

microbiology↗

bioRxiv2023

The vaccinia virus E3L dsRNA binding protein detects distinct production patterns of exogenousand endogenous dsRNA

Double-stranded RNA (dsRNA) is a pathogen associated molecular pattern recognized by multiple pattern recognition receptors and induces innate immune responses. Viral infections can generate dsRNA during virus replication. Genetic mutations can also lead to endogenous dsRNA accumulation. DsRNA is present in multiple conformations such as the A form (A-dsRNA) or Z form (Z-dsRNA). A-dsRNA has been detected from multiple viruses with positive-stranded RNA genomes (+ssRNA) but rarely from viruses with negative RNA genomes (-RNA); Z-dsRNA can be detected from influenza virus and poxvirus infections. Viruses have evolved mechanisms to antagonize cellular antiviral responses triggered by dsRNAs. For example, the vaccinia-virus E3L protein can bind and sequester dsRNA to evade host immune responses. The E3L protein encodes a Z-DNA and a dsRNA binding domains that bind to Z-form nucleic acids or dsRNA, respectively. Here we developed recombinant E3L proteins to detect dsRNA and Z-dsRNA generated from viral infections or endogenous cellular mutations. We demonstrate that the E3L recombinant protein specifically detects A-dsRNA generated from +ssRNA viruses but not-RNA viruses. We observe that among various virus infections assayed, only the influenza A virus generates Z-RNA that can be detected by anti-Z-NA antibody but not by the E3L recombinant protein containing the Z-DNA domain. The E3L recombinant protein can also detect endogenous dsRNA in PNPT1 or SUV3L1 knockout cells. Together we concluded that A-dsRNA can be produced and detected from viruses with +ssRNA genomes but not-RNA genomes, and Z-dsRNA can be produced and detected from influenza A virus. ImportanceThe detection of dsRNAs, which exist in the A-dsRNA or Z-RNA conformation, is important for the induction of innate immune responses. dsRNA are generated during a virus infection due to virus replication, or can accumulate to genetic mutations. We engineered recombinant vaccinia virus E3L protein that can detect A-dsRNA generated during infection with a positive-sense RNA genome virus but not a negative-sense RNA genome virus. Infection with influenza A virus generates Z-RNA that can be detected with an anti-z-antibody but not the E3L recombinant protein. The E3L recombinant protein also detects endogenous dsRNA in PNPT1 or SUV3L knockout cells. These findings highlight important characteristics of dsRNA structure and detection.

microbiology↗

bioRxiv2022

Infection of primary nasal epithelial cells differentiates among lethal and seasonal human coronaviruses

The nasal epithelium is the initial entry portal and primary barrier to infection by all human coronaviruses (HCoVs). We utilize primary nasal epithelial cells grown at air-liquid interface, which recapitulate the heterogeneous cellular population as well as mucociliary clearance functions of the in vivo nasal epithelium, to compare lethal (SARS-CoV-2 and MERS-CoV) and seasonal (HCoV-NL63 and HCoV-229E) HCoVs. All four HCoVs replicate productively in nasal cultures but diverge significantly in terms of cytotoxicity induced following infection, as the seasonal HCoVs as well as SARS-CoV-2 cause cellular cytotoxicity as well as epithelial barrier disruption, while MERS-CoV does not. Treatment of nasal cultures with type 2 cytokine IL-13 to mimic asthmatic airways differentially impacts HCoV replication, enhancing MERS-CoV replication but reducing that of SARS-CoV-2 and HCoV-NL63. This study highlights diversity among HCoVs during infection of the nasal epithelium, which is likely to influence downstream infection outcomes such as disease severity and transmissibility.

microbiology↗